Objective To evaluate the effects of mini-open anterior lumbar interbody fusion (ALIF) in the treatment of recurrent lumbar disc herniation (RLDH).Methods From February 2001 to February 2012,20 patients of RLDH who underwent mini-open ALIF were retrospectively analyzed.There were 8 male and 12 female with an average age of 53.1±5.9 years (range,44-68 years).The SynFrame retractor system and SynFix-LR interbody cage were used in operation.The operative time,intraoperative blood loss,blood drainage of 24 hours postoperatively and hospital stay were recorded.In addition,visual analogue scale (VAS)and Oswestry disability index (ODI) of pre-operation,2 days,3,6 and 12 months postoperatively were evaluated.Results All patients were followed up for 12-110 (average,45.6±29.6) months,postoperative VAS score and ODI percent decreased significantly comparing with that of pre-operation (P＜0.05).However,no remarkable difference (P＞0.05) was found among that of 2 days,3,6,12 months postoperatively.Average VAS score was 7.7±0.7 before operation and 1.7±0.9 at 12-month follow-up.Average ODI percent was 80.6％±3.9％ before operation and 6.6％± 1.3％ at 12-month follow-up.Intraoperative blood loss was 90-220 ml (average,126.0±40.3 ml) and postoperative blood drainage at 48 h was 35-63 ml (average,47.5±7.6 ml).Hospital stay was 4-11 days (average,6.7± 1.8 days).All patients had achieved solid fusion after 6 months' follow-up.All these implants were in good places without displacement or hardware failure.Conclusion Mini-open ALIF can result in fewer invasions,significantly relieve symptoms and improve patients' function in the treatment of RLDH.Moreover,it can increase fusion rate with fewer complications,which can obtain a satisfactory short-or mid-term effect.

Objective To explore the possible pathological essence of HIZ in lumbar intervertebral disc by means of CT,MRI and histomorphology analysis.Methods All of 41 patients of low back pain with the HIZ in the lumbar disc on MRI were identified.There is 23 males and 18 females with mean age of 38 years (range 33-50 years).All the patients were divided into 2 groups according to the characteristics of HIZ on MRI:group A,29 patients with high intensity on MRI T2WI and low intensity on MRI T1WI; group B,12 patients with high intensity both on T2WI and T1WI.All these patients underwent X-rays and CT scan on the targeted level.26 patients in group A were performed discography and pain provocative test.15 patients in group A and 7 patients in group B underwent operation and those samples of HIZ region were excised for HE staining and immunohistochemical analysis.Results All the patients in group A were proved intervertebral disc degeneration on CT and MRI.21 patients in 26 who underwent discography and pain provocative test were proved positive and 15 of them underwent operation(Transforaminal lumbar interbody fusion or posterior lumbar interbody fusion).Histomorphology examination showed annular tear combined with granulation tissue in the samples of HIZ region which were excised in operation.Neoformative blood capillary could be seen through CD34 staining.Macrophage could be found in CD68 staining,but the regions off the HIZ were less stained.In group B,all those targeted discs showed calcified or ossified lesion on the posterior annular on CT scan,HE staining showed calcification or ossification of the posterior annulus fibrosus with frontier line.Conclusion The HIZ on MRI T2WI with low intensity zone on T1WI possibly refers to annular tear combined with granulation in-growth.But the HIZ both on MRI T2WI and T1WI might be calcification or ossification.The conventional concept of HIZ might be modified as HIZ on MRI T2WI,but low intensity zone on MRI T1WI.In addition,CT scan might be helpful in the distinguished diagnosis.

Objective To assess incidence rate of different types of cement leakage in percutaneous kyphoplasty (PKP) with or without intravertebral clefts and to determine whether basivertebral foramen could be connected with intravertebral cleft.Methods 270 vertebrae in 224 consecutive patients who underwent percutaneous kyphoplasty for treatment of osteoporotic vertebral compression fractures were classified into two groups on preoperative radiographs,computed tomography scans,and/or magnetic resonance images of the treated levels:Cleft group with an intravertebral cleft in vertebral body and trabecular group without intravertebral clefts.On direct postoperative images,the patterns of cement leakage were classified as 5 types:through a cortical defect into paraspinal soft tissues (type A),through the basivertebral foramen (type B),via the needle channel (type C),through a cortical defect into the disc space (type D),via the paravertebral vein (type E).The incidence of different types of cement leakage between two groups was analyzed.Results In 72 of 270 vertebrae,an intravertebral cleft was confirmed on preoperative images.Leaks through basivertebral foramen as type B (42,15.5％) and through cortical defects into the disc space as type D leaks (21,7.8％) were more common than other types.The incidence of type B leakage in the cleft group (23.6％) was higher than the incidence in the trabecular group (12.6％),which made a statistical significance (P=0.028).There was no statistical difference between the trabecular pattern and the cleft pattern on other types of leaks.Conclusion Type B leaks were more common in vertebrae with the presence of an intravertebral cleft,which support the presence of the connection between an intravertebral cleft and the basivertebral foramen.Thus,care must be taken when PKP was performed in these patients to avoid cement leakage into spinal canal through basivertebral foramen directly.